The manufacturing, fabrication, and precision engineering sectors have improved due to the efficiency and flexibility afforded by fiber laser technology, especially in laser welding. As one of the most sophisticated solutions for cutting, engraving, and marking, fiber lasers synergize accuracy with speed, enabling industries to boost productivity and obtain complex results. This guide analyzes deeply the inner sides of fiber laser technology starting from its working principle, advantages, and the various industries it serves. It does not matter whether you are a professional in the industry or are just a curious individual; this article will aid you in comprehending the potential of fiber lasers while assisting you in appreciating the reasons these devices are molding industrial processes.
What is a Fiber Laser and How Does it Work?
A fiber laser is a laser that uses an optical fiber doped with rare-earth elements like ytterbium, erbium, or neodymium as the active gain medium. Its functioning involves, first, amplifying the light through the fiber core, which serves as the path for the fire beam. It begins with the generation of high-intensity, coherent light output through the excitation of the dopant ions in the fiber by a pump light. Fiber lasers have exceptional beam quality alongside being highly efficient and having low maintenance requirements, giving them an edge over others in industries like manufacturing, medicine, and communications where high precision is crucial.
Understanding the Laser Beam Mechanism
The production of a laser beam is based on stimulated emission, which is the enhancement of light amplification by photons in a controlled setting. The energy supply is frequently pump light; it makes it possible to energize ions, mostly in the form of electrons, contained in the laser medium. These energized ions discharge a certain amount of energy as photons which get reflected between mirrors so that they may be focused and strengthened. The light is then focused and coherent. Such mechanisms are accurate, therefore, they are best suited for highly demanding tasks that require precise energy input.
The Role of Optical Fiber in Fiber Lasers
The medium where the laser light is produced, directed, and amplified is at the very foundation of fiber laser technology. Optical fibers are the principal components of this technology. The fiber is commonly produced from silica glass which has been doped with rare earth elements, such as ytterbium and erbium, to aid in amplification of light by stimulated emission. One of the primary benefits of such fibers is that they have very high surface-area-to-volume ratios, and as such, when heat is generated and shed from the object, effective thermal regulation becomes possible. This characteristic allows fiber lasers to produce high power outputs while keeping the beam quality superb.
Moreover, the primary design feature of optical fibers guarantees that the produced light remains confined in the fiber core, thus greatly reducing loss and enabling long-distance transfer without marked deterioration. Innovative progress in fiber lasers has resulted in increased power scaling to tens of kilowatts, which are most suitable for numerous industrial applications, including precision cutting, welding, material processing, and others. For example, some industrial experts report that fiber lasers have all but taken over the global industrial laser market, where these lasers have an astounding efficiency of up to 35%, which is vastly superior to other CO2 lasers for instance.
The implementation of actively doped optical fibers enhances wavelength versatility allowing the use of fiber lasers to be across a large spectral range. This flexibility accommodates a broad spectrum of functions such as medical surgery, telecommunications, defense, and even advanced fiber laser architecture. Therefore, optical fibers still serve as a crucial link in the continuum of fiber laser systems and advanced technology with their practical and efficient usage.
Key Components of a Fiber Laser System
Like any technological system, fiber laser systems have multiple integral parts that must work together coherently. Below is a summary of these key components.
Pump source
Pump sources are capable of providing the energy needed for the excitation of ions in the doped optical fiber. Usually, pump sources are high-powered compact, reliable, and efficient, such as semiconductor diodes. For specific applications, the wavelength of the pump source is chosen so that the energy can be optimally absorbed by the doped medium.
Active Gain Medium
In a fiber laser, the doped optical fiber, which is normally clad with a rare earth element, serves as the fiber’s gain medium. The dopants are usually the rare earth minerals capable of issuing the fiber laser’s emission wavelengths, such as ytterbium or erbium. While ytterbium facilitates wavelengths around 1 µm, erbium supports operational wavelengths around 1.5 µm. Further development of doping technologies is making it possible to produce tailored output wavelengths for a variety of precision industrial and medical uses.
Optical Resonator
The optical resonator consists of two mirrors or other reflecting parts which are located at the ends of the gain medium and serve the purpose of light amplification in the cavity. As in all fiber lasers, such an optical resonator is made with the help of fiber Bragg gratings (FBGs) which serve as specific wavelength reflective elements, thus enabling compact size and low losses.
Cooling System
Particularly with high-power models, fiber lasers require effective cooling devices to maintain operational stability and not overheat. Cooling is built into the design of optical fibers owing to the high surface-to-volume ratio. In most high-power configurations, however, external units for water or air cooling are provided.
Beam Delivery System
Accurate transfer of energy to the target by the laser beam delivery system remains essential for industrial purposes. Optical fibers along with fine-tuned collimators are used to ensure precise transfer with minimum energy loss alongside high-quality beam focus.
Control Electronics
Advanced electronic controllers designed for power applications with adjustable controls for power levels, emission duration, and system diagnostics are standard in modern-day fiber lasers. These controllers not only improve a system’s stability but also make it user-friendly for seamless integration into other automation systems.
Example Performance and Applications
As a reference, cutting-edge automated fiber lasers have been known to reach power exceeding 100 kw with M² factors close to 1, and with advanced fiber laser architecture. This shows how accurate they are for metal cutting and welding processes done at high speeds. Also, together with the ability to use other wavelengths, such as erbium-doped systems at ~1.5 µm for telecoms, highlights their versatility.
Types of Fiber Laser Technologies
Differentiating Pulsed Fiber Lasers from Other Types
Pulsed fiber lasers, unlike CW lasers, possess the nuanced capability to emit light in pulses; these pulses can be a few nanoseconds, picoseconds, or femtoseconds long, depending on the laser type and application. The most distinguishing characteristic of fiber lasers is their ability to deliver exceptionally high peak power while maintaining a low level of thermal damage on the material being processed. For instance, fiber lasers that operate on a pulse interval of a few nanoseconds have pulse energy output ranging between 0.1 to 1 mJ, with repetition of several kHz to MHz. This makes pulsed fiber lasers suitable for tasks like micromachining, engraving, and marking.
Ultrafast lasers operating in the femtosecond range are well suited for applications that require sub-micron precision, like manufacturing semiconductors or medical devices. Still, for more delicate processes such as drilling or cleaning, pulsed fiber lasers have been shown to outperform CW fiber lasers in the reduction of the heat-affected zone (HAZ) suffered. This characteristic is also useful when working with thin materials and crafting fine textures on surfaces.
The multifunctional nature of pulsed fiber lasers makes them efficient enough for use in aerospace, electronics, and healthcare – industries that require precision and low thermal damage. The compact structure, reduced upkeep, and energy efficiency also aid in their adoption for contemporary industrial tasks.
Exploring High-Power Fiber Lasers for Industrial Use
Due to the continual advancement, performance, and efficiency of high-power fiber lasers, they have integrated into modern systems and industrial processes unlike before. High power fiber lasers can deliver power outputs cubing hundreds to thousands of watts. This makes them fit for demanding tasks like welding, cutting, and additive manufacturing processes. Their efficiency at elevated power levels guarantees consistent precision and reduces material waste which is crucial for industries like aerospace and automotive manufacturing.
High-power fiber laser also has an edge over other counterparts because of their energy efficiency. For example, the wall plug-enabled efficiency of a fiber laser ranges from 25-to 35%. In comparison to CO2 or solid-state lasers, it surpasses significantly and not only reduces operational energy consumption but also cooling requirements. This leads to a significant decrease in overall costs.
Moreover, cost and maintenance-wise, high-power fiber lasers are inexpensive. This is due to the robust, monolithic design without any moving parts that are remarkably durable, leading to minimal maintenance issued during operations. This flexibility enhances productivity in industrial processes, leading to an increase in average operational lifetime.
Modern innovations in fiber laser technologies have automated monitoring and provided real-time adaptive output control, which boosts performance in complex activities. For instance, these improvements are especially useful in creating sophisticated parts needed in the medical devices industry and elaborate components in the aerospace industry, both of which have stringent quality requirements.
The use of high-power fiber lasers also enables eco-friendly practices in industries. Their accurate delivery of energy and low heat exposure minimize wastage and aid in green engineering. The continued acceptance of these lasers in different fields for fiber manufacturing showcases their versatility, reliability, and efficiency, confirming their contribution to technological advancement.
Comparing Solid-State Lasers with Fiber Lasers
Construction and Design
Crystal or glass serves as a solid gain medium for solid-state lasers while for fiber lasers, optical fibers doped with rare-earth elements like erbium serve as the medium. The compactness of the design offered by fiber lasers is greater as compared to solid-state ones.
Efficiency
When compared to solid-state lasers, fiber lasers are usually more efficient, converting energy into laser power to a higher degree resulting in lower operational costs and less energy wastage.
Beam Quality
Superior beam quality is provided by fiber lasers which result in better direction, precision, and control in cutting, welding, and engraving. While capable of high-performance quality, solid-state lasers need a more time-consuming setup in comparison to fiber lasers.
Durability & Maintenance
With durable design and low maintenance due to a contained optical path with no moving components, fiber lasers are easy to maintain. This is not the case for solid-state lasers which need more constant modifications and repairs.
Applications
Medical procedures and scientific research are two common fields with high peak power that enable the usage and solid-state lasers. Fiber lasers are the best option for industrial applications like precision manufacturing and materials processing.
The accuracy the above statements provide gives an edge to fiber lasers over modern industrial use while still allowing solid-state lasers to serve their precise niche functions.
Applications of Fiber Laser in Various Industries
How Laser Cutting Transforms Manufacturing
Laser-based cutting and engraving systems provide a faster, more accurate, and more flexible way to shape material which greatly improves the manufacturing process. This technology performs accurate and precise cuts and produces clean edges that do not require too much finishing work. This technique applies to various types of metals, plastics as well as composite pieces, and so can be used in different industries. Moreover, laser cutting aids in the reduction of excess materials used, causes an increase in the speed of production turnaround time and makes materials less expensive. All of these factors combined lead to increased efficiency in productivity across a wide range of industries.
The Role of Laser Engraving in Customization
With its precision and versatility, laser machines can customize anything from jewelry to electronics, and promotional products. This is done through the use of a focused beam laser that etches text, patterns, or designs on surfaces without physically coming in contact with the material. Several industries have adopted laser engraving to promote customization.
Customization is made easy with laser engraving since it can be used on a variety of materials such as metals, glass, wood, leather, acrylic, etc. Advanced laser systems are capable of achieving engraving depths of up to 0.1mm. Sharp and detailed results are produced. In manufacturing, laser engraving has found widespread use for serial numbers, barcodes, and logos where traceability and brand consistency are needed.
Consumer demand for one-of-a-kind products is on the rise which means the global market for laser engraving services will grow. Companies with modern laser engraving technology report a 30% reduction in production times as compared to businesses using traditional methods. High-powered lasers and automated systems facilitate bulk order processing while maintaining output quality. The fast-paced customization-driven economy of today highlights the importance and impact of laser engraving.
Advancements in Laser Marking Technology
In the last few years, the advancement of precision, efficiency, and flexibility, especially through seed lasers, has transformed marking technology. One of the most notable changes has been the adoption of fiber laser systems, which are much more energy-efficient and have a longer service life than CO2 lasers. Fiber lasers are now capable of marking at high speeds and with great detail, even on difficult materials such as plastic and metals which are used in the aerospace, automotive, and electronics industries.
The introduction of software-driven automation is another important milestone. These smart-systems integrate with CAD files for marking logos, patterns, and barcodes while eliminating the need for manual work and drastically reducing the chances of human error. According to industry reports, automated systems for laser marking have managed to increase production throughput by over twenty-five percent, proving to be highly beneficial in high-scale production settings.
The use of UV laser markers is expanding thanks to their capability to create high-contrast marks even on delicate heat-sensitive materials. Such systems are especially useful in the medical device manufacturing sector which requires material and spatial accuracy. Additionally, having green lasers available has greatly aided in the marking of glass and other reflective surfaces where problems such as cracking and distortion will be avoided.
As the need for traceability and compliance increases, particularly in the pharmaceutical and defense industries, laser marking technology becomes essential. It provides a solution for traceable, permanent, and non-tamperable markings while conforming to the needed industry standards regarding strength, durability, and readability. These advancements in technology make laser marking tools essential for modern manufacturing processes, creating a new standard to be met in terms of quality and innovation.
Choosing the Right Fiber Laser Machine
Evaluating Laser Power for Different Applications
Deciding the laser power is a very important step if one is aiming for precise marking and engraving outcomes. Power level is dependent upon the material to be marked as well as the quality, depth, and marking to be achieved. A fiber laser has a power output from 20W to 100W and certain power level combinations are designed for specific uses such as:
- Low Power Lasers (20W – 30W): Perfect for marking subtle designs onto materials like thin plastics, metals or electronic parts. Such lasers will mark the material with no damage or Mark distortion, therefore these lasers are suitable for designs that are complex or precise, such as those found in medical devices, microelectronics, etc.
- Mid-Power Fibers (30W – 50W): This range of lasers is quite versatile and very common as, it is useable on aluminum, stainless steel, brass etc. They get selected for low to moderate engraving depth that includes permanent markings like barcodes, logos, and serial numbers on industrial products. According to research, mid-power fiber lasers mark very quickly and are also energy efficient.
- High-Power Lasers (50W-100W): Intended for industrial use, these lasers specialize in deep engraving as well as high-contrast marks and cuts on extremely tough substrates, for example, titanium or carbon steel. They are regularly used in aerospace and automotive industries where powerful lasers are necessary to preserve the reliability and identifiability of vital parts under severe stress. For example, a 70W laser can engrave hard steel to a 0.5mm depth in less than a second which illustrates the efficiency of such lasers in difficult conditions.
Another important factor for laser power selection is the thermal conductivity and reflectivity of a material. Notably, highly reflective materials, for instance, gold, silver, and copper usually require more powerful lasers with longer pulse widths for best absorption. On the other hand, anodized aluminum, which is relatively less reflective, can be worked on with far less power for better efficiency.
Correct estimation of laser power enables desired quality levels to be achieved while reducing material waste and operational costs. Material tests and power level adjustment simulations should be performed by manufacturers to ensure the power level meets their production needs.
Understanding Laser Parameters for Optimal Performance
Key Laser Parameters to Consider
Power density is one of the parameters that require particular attention because the interaction of material with energy is a function of its distribution over a surface area. The required level of power density needs to be set to achieve precision and efficiency with processes such as cutting and engraving.
- Different materials have specific wavelengths over which they absorb laser energy. Selecting a particular wavelength will determine if the material will be processed effectively, therefore, ensuring the appropriate wavelength should be selected.
- For fine, heat-sensitive processing, shorter pulses are ideal with pulsed lasers, while tasks that require longer energy transfer periods are better suited with longer pulses.
- Energy needs to be focused on the desired area with maximum concentration which will be achieved with correct focusing. This objectively determines accuracy and quality.
It is possible to remain efficient in operations and achieve high-quality results consistently by optimizing these parameters depending on the material and application.
Considerations for Selecting a Fiber Laser Cutter
In choosing a fiber laser cutter, I emphasize the output power since it dictates the type and thickness of materials the machine can work with. I also examine the machine’s compatibility with the materials that I work with in terms of wavelength and beam quality. Moreover, the system’s precision and cuting speed are vital in achieving the production targets seamlessly. Finally, I consider the system’s reliability and ease of use in terms of software integrations and maintenance needs.
Future Trends in Fiber Laser Technology
The Impact of Laser Technology on Innovation
With precision manufacturing processes, increased accuracy, and reduced production times, laser technology has impacted virtually every industry. Some of the most important applications are found in medical devices both for lasers in surgery and in diagnostics and electronics for microprocessing and component assembling. Moreover, advanced lasers provide innovation in renewables through their application in solar cell manufacturing and communication systems by fiber-optic technology. All these developments highlight the important contributions of lasers in improving productivity and creating new opportunities in many fields.
Emerging Laser Applications in New Sectors
There is an emerging use for lasers in various industries owing to the ease and speed with which their technology is advancing. Such advancement allows for the modernization of certain processes. In additive manufacturing, particularly in metal 3D printing, the use of high-powered lasers is essential. This application leads to a variety of benefits, such as the ability to create intricate shapes, the possibility of using superior quality materials, and the making of less waste. The overall metal additive manufacturing industry is expected to grow at a rate of 20.3% annually until 2028 due to the many improvements in laser technology.
There is another developing area where this is applicable, which is precision farming which utilizes technology in agriculture. The ability for lasers to detect the health of plants, and the condition of soil, and even act as invasive pest control measures makes their use in agriculture invaluable. These practices are in line with the current trend of sustainable farming since they improve resource efficiency as well as increase crop yield all while minimizing the use of farm resources.
Besides surgery and diagnosis, lasers are now also being integrated into other areas in the medical field. Examples of such use include laser-guided bioimaging, where lasers are shone on a tissue to give high-resolution images at the cellular level, and laser vasculature-targeted drug delivery, which involves targeted low-level laser illumination onto specific tissues to enable ease of treatment. These recent innovations promise higher levels of precision and lower recovery times for patients.
Eventually, the use of lasers in environmental monitoring and sustainability has sparked some interest. For example, laser-induced breakdown spectroscopy (LIBS) is changing the way pollutants in air, water, and soil are analyzed. This technique offers very fast and, most importantly, real-time data crucial for proactive ecological management. In addition to the growing interest in environmental preservation, efforts to develop these laser-based solutions have increased.
The wide-ranging applications in different areas emphasize not only the multifunctionality of laser technology, but also his ability to solve multifaceted problems within science, industry, and society.
Challenges and Opportunities in Fiber Optic Development
The development of Fiber optic cables faces issues such as expensive installations and ongoing maintenance, especially in rural or less developed areas. Also, without proper infrastructure, the damage fiber optics cables are prone to, as well as the distance the signal has to travel causing attenuation, makes them unreliable. These problems require further funding for highly durable materials along with well-optimized network infrastructures.
On the other hand, there is plenty of opportunity for investment due to the increase of people using the internet, streaming, and cloud services. The progress in physics that relates to materials science as well as, fiber optic amplification technologies, will further increase performance and decrease prices. Also, the use of fiber optics for 5G networks and smart city systems offers global enablements for technological improvement just like the advancement in laser cleaning technology has shown.
Frequently Asked Questions (FAQs)
Q: What distinguishes a fiber laser from a CO2 laser, and what is a fiber laser?
A: A fiber laser is a type of laser that employs fiber optic cable as the active gain medium and is typically supplemented with pump laser diodes. As opposed to CO2 lasers, which rely on a gas mixture, fiber lasers utilize custom-made optical fibers doped with rare gases such as erbium for particular applications. Fiber lasers are more efficient, have shorter wavelengths, and need less maintenance than CO2 lasers and thus are optimized in laser cleaning tasks. They are also exceptionally good at cutting metals with unmatched precision and beam quality.
Q: What steps are taken by a fiber laser engraving machine to realize its purpose?
A: Fiber laser engraving machines mark or engrave different materials using fiber laser sources. The engraving of the material is done by directing the vaporizing laser beam onto it, while the laser light produced is further amplified and focused through a laser cavity. The engraving machines alter and vaporize a wide range of different materials such as metals and plastics with great speed and accuracy due to the innovative design of the laser cavities that enables the focused laser beam to be directed to the surface of the material.
Q: What are the most important elements of the fiber laser system?
A: The most important components of the fiber laser system are: 1. Laser Diode: Supplies the pump light, 2. Doped Fiber: Functions as the medium for light amplification, 3. Fiber Bragg Grating: Selects the wavelength and gives feedback, 4. Fiber Amplifier: Uses active fiber technology to increase the power of the laser, 5. Beam Delivery System: The laser is focused on the workpiece area, 6. Laser Resonator: Increases and modifies the output of the lasers. All of these elements are combined and coordinated to control, generate, and amplify the laser light for numerous applications.
Q: What are the pros of operating a 20W or 50W fiber laser?
A: Different applications benefit from the use of 20W and 50W fiber lasers in several ways: 1. Efficiency, low power consumption 2. Precise cutting and engraving with excellent beam quality 3. Minimum maintenance 4. Long operational lifetime 5. More compact than other lasers 6. Wide scope of materials processed For engraving and marking tasks that are not too deep, 20W fiber lasers would be suitable. But for more demanding cutting and engraving tasks with thicker and harder materials, 50W fiber lasers are more appropriate.
Q: What are the distinctions between fiber laser marking machines and other laser marking technologies?
A: A fiber laser marking machine has more benefits over other laser marking technologies such as: 1. Greater efficiency and lower operating expenses than other CO2 or crystal lasers 2. Greater beam quality which results in finer and more precise marks. 3. A combination of multiple laser configurations makes it possible to mark a wider range of materials such as metals, plastics, and even ceramics. 4. Increased peak power results in increased marking speed. 5. Increased operational lifetime while reducing maintenance. 6. Smaller size which enhances integration into production lines. These features make fiber laser marking machines increasingly popular for industrial applications.
Q: What are the different types of fiber lasers and their applications?
A: The different types of fiber lasers include 1. Ytterbium-doped, which is typically used in cutting and welding metals. 2. Erbium-doped, used for telecommunication and medical purposes. 3. Thulium-doped, suitable for medical and sensing applications. 4. Holmium doped, used in medicine and military applications. 5. Pulsed fiber lasers, ideal for marking, engraving, and micromachining. 6. Continuous wave fiber lasers, which are used in cutting, welding, and additive manufacturing. Each of these lasers has specific wavelengths and characteristics that allow its use in different applications such as manufacturing, telecommunications, and healthcare.
Q: What classifies single-mode fiber lasers and multi-mode fiber lasers as both distinct?
A: Single-mode and multi-mode fiber lasers vary in their beam qualities and applications: 1. Beam quality: Single-mode lasers deliver a better, more concentrated beam 2. Power output: Multi-mode lasers are known to produce a higher power output 3. Fiber core diameter: Single-mode fibers possess a narrower core diameter 4. Applications: Single-mode lasers work best for precise cutting and welding while multi-mode lasers are best suited for high-power applications such as cutting thick metal 5. Cost: Single-mode lasers are usually more costly due to the high precision parts they have The selection of single-mode or multi-mode depends on the needs of the application.
Q: What are the advantages of using fiber lasers for industrial applications?
A: Fiber lasers excel in numerous aspects when it comes to industrial use: 1. Optimal cost: efficiency ratio and lower operational expenses 2. Accurate processing due to high-quality beams 3. Low maintenance costs 4. Extended operational life (up to 100,000 hours) 5. Reduction of physical space for machinery results in easier system integration 6. Diverse material processing capabilities including reflective metals 7. Increased efficiency due to rapid speeds 8. The multi-purpose feature facilitates cutting, welding, marking, engraving, and cleaning. All listed benefits contribute to the growing implementation of fiber lasers in manufacturing, automotive, aerospace, and other industries.
Reference Sources
1. Properties Of Fabry Perot Laser With High Pump Lasers For Enhancing Fiber Optic Transceiver Systems
- By: Mahmoud M. A. Eid, A. Rashed, Araf Shafkat, K. Ahmed
- Published On: September 21, 2020
- Publication: Journal of Optical Communications
- Citation Token: (Eid et al., 2020)
Overview:
- The purpose of this research is to analyze the characteristics of Fabry Perot lasers about high pump lasers and their applicability to improving the productivity of fiber optic transceivers.
- The authors concentrated on the geometrical parameters of the light source such as active layer depth, width, and length to maximize their efficiency.
- The results of the analysis revealed that an active layer depth of 0.06 cm with a width of transmission and reception signal efficiency of 1.5 × 10⁻⁴ cm results in optimal signal strength.
2. Recent Progress of Dynamic Mode Manipulation via Acousto-Optic Interactions in Few Mode Fiber Lasers: Mechanism, Device and Applications
- By: Jiafeng Lu et al.
- Published on: 24th November 2020
- Published in the Journal of: Nanophotonics
- Citation Token: (Lu et al., 2020, pp. 983–1010)
Summary:
- The review presents the latest developments in dynamic mode manipulation in few-mode fiber lasers with acousto-optic interactions.
- The authors have pointed out the importance of the control of spatial mode generation in the context of high-capacity space division multiplexing.
- This review encompasses mechanisms, devices, and applications of the use of acousto-optic interactions that are capable of fast-mode tuning and dynamic switching.
3. Fiber-optic distributed sensor based on hybrid Ramon and bullion scattering employing multiwavelength fabry-perot lasers.
- By G. Bolognini, M. Soto, F. Di Pasquale
- September 29, 2009.
- In IEEE Photonics Technology Letters.
- Citation Grabber: (Bolognini et al., 2009, pp. 1523-1525)
Roughly Speaking:
- This paper presents a design of a distributed sensor system that can measure strain and temperature simultaneously, based on multiwavelength Fabry–Pérot (FP) lasers.
- The authors show that the longitudinal modes of the lasers can self-activate and improve the quality of the spontaneous Raman scattering measurement.
- The experimental results confirm dramatically better results in simultaneous measurements, and thus, validate the system.
